Deadly 'superbugs' destroyed by molecular drills: Study

Molecular drills have gained the ability to target and destroy deadly bacteria that have evolved resistance to nearly all antibiotics. In some cases, the drills make the antibiotics effective once again.

Researchers at Rice University, Texas A and M University, Biola University and Durham (U.K.) University showed that motorized molecules developed in the Rice lab of chemist James Tour are effective at killing antibiotic-resistant microbes within minutes.

According to researchers, "These superbugs could kill 10 million people a year by 2050, way overtaking cancer," Tour said. "These are nightmare bacteria; they don't respond to anything."

The motors target the bacteria and, once activated with light, burrow through their exteriors.

The researchers reported their results in the American Chemical Society journal ACS Nano.

Tour and Robert Pal, a Royal Society University Research Fellow at Durham and co-author of the new paper, introduced the molecular drills for boring through cells in 2017. The drills are paddlelike molecules that can be prompted to spin at 3 million rotations per second when activated with light.

Tests by the Texas A and M lab of lead scientist Jeffrey Cirillo and former Rice researcher Richard Gunasekera, now at Biola, effectively killed Klebsiella pneumoniae within minutes. Microscopic images of targeted bacteria showed where motors had drilled through cell walls.

"Bacteria don't just have a lipid bilayer," Tour said. "They have two bilayers and proteins with sugars that interlink them, so things don't normally get through these very robust cell walls. That's why these bacteria are so hard to kill. But they have no way to defend against a machine like these molecular drills, since this is a mechanical action and not a chemical effect."

Tour said the nanomachines may see their most immediate impact in treating skin, wound, catheter or implant infections caused by bacteria -- like staphylococcus aureus MRSA, klebsiella or pseudomonas -- and intestinal infections. "On the skin, in the lungs or in the GI tract, wherever we can introduce a light source, we can attack these bacteria," he said. "Or one could have the blood flow through a light-containing external box and then back into the body to kill blood-borne bacteria."

Cirillo said, "We are very much interested in treating wound and implant infections initially, but we have ways to deliver these wavelengths of light to lung infections that cause numerous mortalities from pneumonia, cystic fibrosis, and tuberculosis, so we will also be developing respiratory infection treatments.